Maybe I did something wrong and broke the chips, but could you please help? I wired it all up, with the reset and master clock signals running through the quad buffer chip to amplify them. The quad buffer (HCT125) is powered from the 5V supply from the teensy, and the clock and reset signals are connected to the inputs. The inverter pins are not wired at all, and the master clock signal comes from one of the PWM pins from which I try to produce a 12MHz signal. The OPL3's supply pin is also connected to the 5V source, and all other pins are connected either to the teensy or the quad buffer. They're all connected directly, i.e. no capacitors or resistors are present.

//edit: I should say that the problem is that I don't get the SY signal to work.

Hi, I don't know how this Teensy environment works, but my guess is the serial port writes are not buffered, so at 9600 bps, each byte sent to serial port takes about 1.04 milliseconds to transfer, and the SY polling must be done at twice the SY frequency, ~3.6MHz. There's no time for sending serial data, or do nothing much else than just receive the serial bits.

In practice, the SY is not 50% duty square wave, it is 25% duty square wave, so that's why it needs to be polled at ~7.2 MHz.

To capture the data stream, I'd take a look at which hardware module could do it. SPI module is one, but not so convenient solution.

I'm aware that the current solution is "suboptimal" (to say the least), but the SY doesn't seem to be triggered at all. In fact, I don't seem to get the OPL to do anything at all, as the outputs from the chip are never changing. I'm still trying to get it to do something, and only then I will start fiddling around with reading/transmitting the data.

Well, unfortunately not. The only thing I have at hand is a voltmeter, which isn't of any use anymore, because the soldering points are properly connected. It was my first though to also buy an oscillosope, but everything I found was too expensive for the budget I've set. I'll try to play around with the PWM pins though, as I think I'm not programming them correctly.

Hm, OK, I managed to get the PWM pin 3 working at 12 MHz and it's producing a nice sine wave. I tried to hook that up to the 74HCT125, but then I realized I need to change the "working point" of the input, because all I get is either HI or LO, independent of the output enable pin (which I hooked up to the PWM pin). The buffer's input should then be the 5V supply from the teensy, the output hooked up the the OPL's master clock, but what should the buffer's supply voltage be, 3.3V, 5V or GND?

I'm a bit overwhelmed by the complexity of hooking it up, so maybe I'll get it working in 2-3 years, once I managed to learn electrical engineering